Under a Cold Dark Moon
by thatdamfangirl23
Summary: Reyna told him it was just the bites that transferred lycanthropy. she was right, wasn't she?
1. Chapter 1

**I had this random idea in bed the other night because I thought it would be interesting. I always did wonder what happened to those werewolf scratches Nico got from Lycaon. This may just stay as a one shot, or I might turn it into a multi chapter story. to be honest, I should probably be updating my other crossover instead of writing this, but hey! Enjoy and please tell me what you think.**

 _Werewolf_

 _[ˈwɛːwʊlf, ˈwɪəːwʊlf, ˈwəːwʊlf]_

 _NOUN_

 _Werewolves (plural noun) · werewolf (noun) · werewolves (plural noun)_

 _(In folklore) a person who changes for periods of time into a wolf, typically when there is a full moon._

Nico stared at the dictionary Annabeth had lent him. His mind raced over that one word again and again. _Werewolf_. They existed of course. Every demigod who wanted to stay alive knew that and he and Reyna had the misfortune to meet a pack during their long journey back to America with a 40 foot tall giant woman who threatened to smite them every minute. Werewolves weren't impossible to defeat – all you had to do is use silver on them – but due to the fact Nico didn't happen to have any silver on him at that exact moment, he had been at a clear disadvantage until Reyna had the genius idea of strapping silver coins to her dagger. Reyna's extreme intelligence was beside the point though. The point was, Nico had been scratched. And not just any werewolf, oh no. Nico just had to be maimed by the king – Lycaon. Typical. The fates really hated him.

The dim light of the Hades cabin cast shadows across the dog eared book and one of the torches on the wall flickered and died. Nico shivered. Through the window, he could hear shouts of glee coming from the campfire where Percy would inexplicably be singing some stupid song that involved grandmas and armour and being the seaweed brain he was. Nico wouldn't be there. He couldn't.

Every time he dared to think he could find acceptance, he was just shut out again. After the titan war, he had quickly overstayed his welcome and withdrawn to the underworld. Even now, after all he went through at the hands of Gaea's army and after everything he had done for camp half blood, they still shot him disgusted glances and looks of fake pity. No. a child of the underworld could never belong with the living. Especially if the suspicion Nico had was correct.

Reyna had told him scratches didn't transfer lycanthropy. He had believed her. Why wouldn't he? Now, he was having his doubts. Once in the lotus hotel, he had read a fantasy novel which listed the symptoms of lycanthropy.

· No illnesses – check. Since the fight, Nico had noticed he was not getting ill. Sure he did try to spend as much time as possible in the infirmary to see Will, but he was rarely ill.

· Animalistic instincts – check. The ghost king once found himself growling at Percy during one of their friendly sparring matches which was incredibly awkward and caused a lot of questions which he couldn't answer. Another time, he had scared Hazel half to death with a sudden roar that came out of nowhere. (The same noise had caused Frank to turn into a lion and try to match it, terrifying poor Hazel even more.)

· Need to kill – check. Recently, Nico had a rather disturbing lust for blood and murder. When there was a smaller animal nearby, he felt the need to tear it from limb to limb in a way that caused even a child of Hades to have nightmares.

There were many more symptoms which Nico couldn't be bothered to name but found himself experiencing in recent months. On the next full moon he came to a final conclusion. It was just a shame he was too late. Pale skin turned to ebony fur, shadows leapt joyfully towards him and a low whimper escaped his gaping throat.

A soulless howl echoed through the night like a plead for help, but no one answered the call.

Nico woke up miles from camp half blood with no memory of what he had done.

He assessed his surroundings, trying to work out where he was. From the trees and grassy ground, Nico assumed he was in some sort of forest, but the noises of a bustling city told him otherwise. His head fuzzy from his furry situation, Nico stumbled out into a clearing, straight into a girl.

She wasn't anyone exceptional. It wasn't one of those happy ever after stories where guy meets girl in a wood, they fall in love and live happy ever after at all. Nico didn't even like girls that way! This particular specimen of the female gender had chocolate coloured skin and frizzy hair in two pigtails. She was wearing a sleeveless top, ripped jeans and converse trainers, giving her an 'I don't care' vibe. The only thing that was vaguely special about her was the scratches on the side of her neck. They looked like… it was almost like someone had… bitten her? It was these scratches that caused Nico to look up and decide to say something. He opened his mouth and something very intelligent like "uh…" came out.

The girl laughed. "Uh, to you too! Now, what are you doing in some woods at four in the morning?"

Nico frowned. "I could ask the same of you."

"I have an excuse."

"What?" Nico asked challengingly.

"What would you say if I said I was a werewolf?" she said in a joking manner. Nico winced and rebounded quickly. This did not go unnoticed by the girl. "You flinched." She noted. Nico simply nodded. "You know about the shadow world?"

"The what?" Nico asked in confusion.

She shook her head in exasperation. "You don't know. I'll be leaving now."

"Wait!" Nico shouted. "Don't go. You said werewolf… are you one too?"

Now it was the girl's turn to recoil. "So you do know about the shadow world."

"I don't know what you're talking about." Nico insisted. "All I know is that I transformed last night and woke up here. I've been having symptoms of lycanthropy for months and I got scratched during a fight with the freaking king of werewolves. Yes I'm a werewolf, yes I know what they are, and could you just tell me what the heck is going on before I stab you?"

She put her hands up. "Jeez. No need to get angry; I think I'm going to call you small angry child. Cute nickname."

Nico glared, not putting his stygian iron sword down.

She carried on. "The shadow world is a world that exists apart from the mundane or human one. It consists of all the creatures you can think of – vampires, faeries, warlocks and yes, werewolves. There is also a race called Nephilim or shadowhunters who hunt and kill demons. The creatures I mentioned before are called downworlders. Now, you're one of them."

"But…"

"There's this guy I know who puts it this way." She said. "All the stories are true. I'm Maia by the way."

"Nico." Said the demigod, completely bewildered. Gods, monsters, and titans he could deal with. He could even manage different pantheons but this… there was no rational reason as to why he couldn't believe this. After all, if most people heard they were the child of a Greek god, they would laugh and scorn. If he could believe that, why not this? The girl – Maia – put out her hand.

"Come with me, you can join our pack!"

He took it and she pulled him, struggling to keep up out of the clearing and through the trees laughing. Nico shook his head once, and then let all his fears out, running alongside Maia, throwing his head back in pure joy – something he hadn't felt for as long time.

 **And that, my friends, is werewolf Nico! just in case anyone is wondering, if this does end up with more than one chapter, Nico won't get together with Maia. he has Will, she has Jordan and it just wouldn't work. Hope you enjoyed.**


	2. Chapter 2

**So in the end I did decide to carry on with this (and I still haven't updated my other story.) I hope you enjoy the next chapter!**

Maia pulled him through the woods until they were both out of breath (which took a while due to their increased stamina. Panting and laughing like maniacs, they emerged onto a busy high street where cars zoomed up and down and people going about their daily lives gossiped. Opposite the two wolves was a small, rundown Chinese take-away. Maia gestured to it.

Nico scoffed. "Seriously? That's your headquarters?"

"You have to look past the glamour!" Maia told him.

"The what?"

"Just concentrate."

Nico concentrated. He got the feeling he did not want to make this girl angry.

"I can't see anythi- whoa! That… ok. That's weird."

Maia looked on, a grin on her face. "What?" Nico asked.

"Oh nothing." she replied. "I just love watching peoples first times with glamours."

"Glad to know I amuse you." Nico scowled, glaring at her.

"Just come in."

Nico followed her in through the door of what was a Chinese restaurant and she threw open two double doors. It almost felt like a scene from a movie where the camera pans out across the room. Nico saw people drinking, talking, sleeping, kissing, any word ending in -ing you might care to mention. They all had a strange sort of aura about them, like they weren't fully human. And, Nico realised, they weren't. They were all werewolves. All these werewolves living a happy, normal life like ordinary humans – or as Maia had explained in breathless jolts on the way: mundanes. Maia wandered over to a man in the corner. He had ragged hair that stuck up like fur all over his head and a flannel shirt and torn jeans.

"Luke!" Maia shouted. "I picked up another one!"

The man looked over in interest. "Who's this, Maia?

"This is Nico. I met him in the woods."

Luke looked sceptical. "You're sure he's a werewolf?"

"He certainly knows about them." Maia answered. "And yeah. I'm pretty sure."

"Well then Nico," Luke said, turning to the demigod. "Welcome."

* * *

Percy Jackson was having a perfect day until his friend was reported missing. He taught a sword fighting lesson to a group of younger campers who were completely in awe of him (making it very hard to do any teaching) in the morning, and spent the afternoon by the lake with his girlfriend. At about 8:00, Annabeth got to her feet, seeming to remember something.

"Where you going?" Percy asked curiously.

"I lent Nico my dictionary. I need it back." She replied.

Percy snickered. "So you really sleep with it under your pillow then, wise girl?"

"Of course not, seaweed brain." The daughter of Athena said. "I just need it back."

"Yeah right."

"Shut up you idiot."

Percy pouted. "But I'm your idiot."

"Shut up Percy. "

"But I'm your Percy."

Annabeth growled. "Jackson, if you don't shut your mouth right now, I swear I'm going to…"

"Okay, okay. I'll shut up."

"Good." She said and stomped off.

Ten minutes later she was back, dictionary in hand and the anger on her face replaced with a look of worry. She stormed past Percy in the direction of the Big House uttering only the words, "Nico's gone."

"What?" Percy asked, but she was already too far away to answer.

* * *

"So," Maia said. "Make yourself at home. I'll pick you up tomorrow at nine."

Nico grimaced. "That's way too early. I won't even be awake until ten!"

"Deal with it." She replied a small smirk gracing her face. Nico scowled and shut the door in her face. He looked around the tiny apartment he had been given by the wolves. It was small and squat, but it was good enough for Nico. He just needed to put some edgy posters up there and some skull decorations over there… then it would be just like home – not that Nico ever had one. Too tired to do anything else tonight, he slumped down on his bed and fell into the world of sleep.

As usual, dreams plagued the son of Hades. His vision started in camp half blood where Percy, Annabeth, Jason, Piper and all the other major campers were gathered around the old ping pong table in the rec room.

"I already told you!" Annabeth said. "He wasn't in his cabin so I looked around the entirety of camp and he was nowhere to be seen!"

"Annabeth." Chiron chided gently. "There has to be some other explanation."

"I don't see what!" she shouted.

"Well…" Percy said, looking anxious to interrupt his girlfriend. "He does have a history of disappearing."

"I thought he was over that?" Will Solace said hesitantly. "He was perfectly happy last time I checked."

"Maybe he just went to camp Jupiter?" Percy suggested.

"No. he would have told us." Will insisted. Jason nodded in agreement.

"Well whatever the case, we have to find him." Annabeth decided, and no one dared to disagree.

Nico's dreams changed and he was inside what looked like some sort of coffee shop although he couldn't be sure, having never been to one. A girl with vibrant red hair was speaking with a blonde boy, gesturing wildly. Next to them sat two black haired kids who looked like siblings. Beside them, a very… glittery man and a ridiculously pale boy – even paler than Nico who prided himself on looking like a vampire.

This boy interrupted the conversation between the redhead and the blonde and Nico caught the name Maia and Luke. Were these people werewolves too?  
The vision faded just as quickly as it had come and Nico woke, his head full of confusion. He would have to ask Maia about them.

 **Not the longest chapter I've ever done, but I needed something. For anyone wondering, it's set after blood of Olympus. In terms of the mortal instruments, I guess its an AU because its after all the fighting's over, but Simon is still a vampire and Jordan is still alive. it's fanfiction - anything goes! hope you liked it!**


	3. Chapter 3

**Here's the next chapter. I haven't written any Mortal Instruments fanfiction before and I've only read the full series once so the characters may be** **a little** **OCC. (read very) Anyway, enjoy!  
disclaimer: Percy Jackson and The Mortal Instruments are owned by Rick Riordan and Cassandra Clare respectively. Not me.**

As promised, Maia was banging aggressively on Nico's door at 9:00 on the dot. In his bed, Nico groaned and turned over.

"Nico?" Maia shouted. "Hello? Let me in!" the son of Hades, still in his half asleep state, tried to work out what was going on. Why was there a girl knocking on his door this early? Everyone at camp knew he would murder anyone who woke him up before midday so that meant he wasn't at camp. So… where was he?

"Nico? I'm coming in." the girl shouted and Nico sat up in shock as the crash of his door falling down woke him. The girl – Maia, Nico remembered – shook her head at his ruffled clothes and hair, still fresh from a night of being slept on. "You are so lazy." She sighed. "Come on, up!"

Maia tugged his arm and he fell on to the floor in a heap.

"I was sleeping!" he protested weakly.

"And now you're not." She replied with a smirk. "Get some decent clothes on and meet me outside." Maia left, slamming the door shut.

Nico groaned again and reached for his discarded t-shirt and jeans which he had thrown across the room last night and pulled them wearily on. He shrugged on his aviator jacket and hopped into his shoes. Then, he opened the door to find Maia's hand pulling him yet again. Why did she always do that?

She looked him up and down. "You were wearing those yesterday."

Nico scowled. "I didn't exactly plan to wake up miles from my home as a werewolf. I didn't pack a suitcase!" he vaguely registered that he had called camp half blood home but thought no more of it. It was just a turn of phrase. He had no real home there.

"Well," Maia said, "we'll have to go shopping then."

"Yay." Nico cheered sarcastically. "What else are we doing today?"

Maia thought. "I was going to introduce you to my boyfriend and my ex and his girlfriend and her brother and her brother's boyfriend and two others."

"What the hell did you just say?"

"I'm going to introduce you to my friends. Also, you're not homophobic, that's good. Magnus tends to kill people who are homophobic."

"Wait what?" Nico asked, truly confused now. "How do you know I'm not homophobic and - who's Magnus?"

Maia laughed. "You didn't flinch when I said my ex's girlfriend's brother has a boyfriend. And Magnus is that boyfriend. He's a warlock."

"A warlock?"

"Basically a wizard. A sparkly Dumbledore."

Nico put his hands up. "Maia, right now I have no idea what you're talking about and how it relates to Harry Potter. Just shut up."

"Rude, but okay."

She opened the door leading to a street and they walked out onto it. The two werewolves walked to a shop which, Nico realised, was the one from his dream. There was a huge sign over it saying Takis. The odd thing was, mortals seemed to be passing by like it wasn't there. It was a bit like the leaky cauldron or Grimmauld place in Harry Potter. Seriously, did everything in this world have some reference to that? Anyway, they went in and Maia led Nico to a table with six other people. Nico recoiled upon the realisation that they were the exact same people from his dream.

"Nico," Maia said, "meet Clary, Jace, Isabelle, Alec, Magnus and Simon."

"Maia," Nico said. "Could you please stop with the long lists of people I don't know?"

Maia ignored him. "Guys," she continued, "meet Nico."

"Hi!" the red haired one said. Clary, if Nico was correct. "So you're a werewolf?"

"Yeah." Nico replied. "You could say that." The pale boy who was now called Simon looked at him. Nico stared back. Simon looked as if he was contemplating asking Nico something. He decided on it. "How old are you, Nico?"

Nico was taken by surprise. "Um… fourteen, why?"

"Oh nothing." I just thought you might be older. You have that feel about you."

Nico felt himself having an internal panic. Simon didn't know it, but he was absolutely correct. Nico was actually about 90, having been in the lotus casino where time didn't pass for most of his life. Simon seemed suspicious, but he shrugged, seemingly content. Next to him, the sparkly man (as he would always be known to Nico) narrowed his rather disconcerting eyes. They were yellowish with slit pupils, like a cat. Normal humans did not have those sorts of eyes. Nico supposed he must be Magnus the warlock. He quickly turned away to face the siblings.

"Hi, Nico. I'm Isabelle." She said coquettishly.

"Hi Isabelle, I'm gay and you have a boyfriend." Nico replied, deadpanned.

"Just teasing!" she assured him. "I know I have a boyfriend." She said, pecking Simon on the cheek. "But can't a girl have a little fun?"

"Isabelle, please shut up before I'm forced to kill you." The other black haired kid said. "Hi Nico, I'm Alec and this is my boyfriend Magnus."

"Who Alec loves to show off." Said boyfriend added. Alec punched him. "What can I say?" Magnus said. "I'm awesome – I don't blame you."

"Please shut up." Alec pleaded. "Anyway, nice to meet you, Nico, but we have to go. See you around."

"Sure." Nico said. "See you."

The party got up and left, but both Magnus and Simon stayed sitting. When Nico raised a questioning eyebrow, they scowled at him.

Magnus started the interrogation. "Okay, we know you were lying about your age earlier. How old are you really?"

"fourteen." Said Nico.

"I don't believe you."

"Ninety something, but why should I tell you that? Wait… what the… why I am I telling you that?"

Magnus smirked. "Oh the wonders a little truth spell can do. Next question, you're obviously not just a werewolf. I can sense that you're not a faerie or a vampire so what are you? A warlock? I can sense magic of sorts."

Nico, struggling against the spell, growled. "Why do you care what I am?"

"You might be a threat." Simon told him. "We've literally just finished two wars and we do _not_ want to fight again."

"Fair enough, I know how that feels."

"I'm waiting for an answer." Magnus reminded him. Nico thought for a few seconds. He couldn't reveal the existence of the gods. It could be possible that Magnus already knew – he seemed very knowledgeable and old – but he probably didn't and Simon, well Simon seemed like a normal teenage boy with a strange craving for blood and no soul.

"I'm a warlock." Nico lied. "But I have an affinity for necromancy and death." That part at least was true. He was a necromancer.

Magnus stared. "Could you prove it?" he asked suspiciously

Nico met his eyes. "Sure."

He reached down to the ground and concentrated. He felt bones rustle miles underneath him and focused on a random skeleton. A small crack appeared in the floor as a hand clawed its way out of the ground, followed by the rest of its body. The waitress screamed although Nico wasn't sure if it was because of the skeleton or the crack in her floor that she would have to fix. Simon, if it was possible, was even paler, a cold sweat running down his face. Magnus simply looked stunned.

"That – that's a full human!" he whispered in awe. "How powerful are you?"

Nico groaned for the third time that day. He should have kept it low key with a mouse or something. He didn't want to draw attention to himself. He looked Magnus in the eyes again.

"Is that enough proof for you?"

 **so Nico is now a warlock. I didnt know that would happen until it did - even though he's not really. anyway, hope you liked it. I think the next chapter will focus on camp halfblood and what happens after they find out Nico is missing. I have no idea when that chapter will be. I just made the stupid mistake of starting another multi chapter story so...**


	4. Chapter 4

**And, here is the next instalment of this random story. Hope you enjoy it.**

Maia dragged Nico round the shops of New York next. Since he had been dunked in the river Lethe, leaving him with no memories of his childhood and then spending the last few years in an environment where knowledge of mortal shopping was really not needed, Nico had no idea what to expect from a shopping trip. Especially not one with the bossiest and scariest girl he had ever met (Clarisse included). Nico doubted he could say no to her.

This meant that when the two hours they were out came to a close, Nico was laden down with way more clothes than he needed. Maia had insisted he wear colours ("you look like an emo." she had told him when he tried to pick out his usual black skull t-shirt and ripped jeans.) he was now clad in a pair of light blue jeans and a maroon shirt and feeling very uncomfortable.

Next, Maia took him to an apartment where he met another werewolf named Jordan. Maia explained that he was her boyfriend and that he worked for something called the Praetor Lupus which only served in reminding Nico of Reyna.

By now, the sun was beginning to slip down behind the tower blocks, projecting ribbons of deep red and orange across the sky. When Maia and Nico made it back to the Jade Wolf, it was pitch black. They expected everyone to have gone home but instead, they found the restaurant in a state of chaos. Wolves were rushing around, some with knives, some unarmed. Nico swore he saw one already transformed.

Maia ran up to Luke who was directing a group of people out of the door.

"What's going on, Luke?" she asked.

"I got a message from Clary." He answered. "There's been a huge demon attack and she needs backup."

"Oh god." Maia gasped. She turned to Nico. "You stay here."

"Why?" he protested. "I can fight!" Maia raised a disbelieving eyebrow.

"Can you?"

"Yes!" she shrugged.

"I'll give you a chance. Do you know how to transform?"

"I can try." Nico said resolutely.

"Fine. Get a knife or something. We're going in five minutes." Luke added.

It must have been quite a sight to see. Battalions of wolves, some hunched over and furry, some walking on two feet and human. All were snarling, their lips curled back, their bodies ready to fight. Nico marched next to Maia and a guy called Bat. He chose to hide his sword and armour for now in order not to arouse suspicion but when the fight began, Nico was looking forward to getting rid of the restless energy he had accumulated over the last couple of days.

Luke leading, they eventually came to the place Clary had specified – a small clearing in the middle of a forest. It was, Nico realised, exactly where he had met Maia and where this mess had started. The werewolves were met by all the people Nico had met earlier in full black armour – something they called gear. Soon afterwards Simon and a whole legion of bloodthirsty vampires turned up too followed by Magnus Bane who looked thoroughly annoyed. Judging by his appearance, Nico guessed he was in the process of dousing himself in pink glitter when he got the call. The warlock's head and arms were covered in the stuff but there were some bare patches here and there.

Shaking his head at Magnus' stupidity, Nico looked up and almost screamed. Almost. The ghost king did not scream. The cause for Nico's reaction was a grotesque creature, blood red with reptilian skin and fangs dripping with noxious liquid. Nico shuddered to think what it was. On instinct, he reached into the shadows for his sword, needing the familiar blade for a sense of security. It whipped through the air and the monster – no demon – was gone, now just a pile of ash on the floor.

Without waiting to receive questions from the wolves around him, Nico leapt into battle, in the frenzy that came with it. He stabbed and parried and ducked for what felt like hours but was probably a matter of minutes. He found that he could slip in an out of his werewolf form which proved immensely useful. Around him, Nico's friends – could he call them friends? – were fighting. Maia and Luke were clawing at their enemies with vigour. The vampires used their enhanced speed to sneak up on demons and sank their fangs deep into their bodies. Shadowhunters had glowing blades which, not unlike Nico's stygian iron sword, were being thrust around in arcs of destruction.

It just wasn't enough.

Despite their best efforts, demons kept emerging from the ground and Nico's allies kept falling. There was nothing they could do even with Magnus' magic. Nico decided he had to try something else. The trick had worked well in all the major battles he had been in. in fact, the first time he had done it was in this same city back when he was twelve. Gods, that seemed like lifetimes ago.

Like he had done earlier in the café, Nico lifted his hands, concentrated and chanted. The hands started to emerge around him, creating great crevices in the ground. One skeleton was followed by another and that was followed by two more. It wasn't just skeletons though. Nico was surrounded on all sides by pale silvery figures, their presence sending desolation and mournfulness across the forest. The ghost king had his subjects.

The skeleton army moved silently across the battlefield, decapitating demons as they went. The ghost's aura weakened the demons so the others could kill them. Nico himself had thrown aside his guise and was in full armour complete with his terrifying skull gage. He sent out his own aura of death and destruction and his shadowtravel allowed him to pop up anywhere he pleased.

After this rendition, the demons didn't last long. Jace's angel blade stabbed the last one remaining and Magnus closed the hole they were coming from with a flourish.

That was when Nico realised the full capacity of what he'd just done. He registered Maia's voice asking him something and when he didn't respond, yelling. Another voice said something and that was the last thing Nico heard before the perpetual darkness pulled him in and he fell unconscious.

 **I seem to have a bad habit of ending chapters with characters unconscious. Oh well!**


	5. Chapter 5

**It's been forever, I am so sorry. I've been concentrating on another story and I just never got round to updating this one. Anyway, enjoy!**  
 **Disclaimer: I dont own the books. Cassandra Clare and Rick Riordan do.**

Nico slipped in and out of consciousness as the night wore on. Every time his eyes opened, he saw people around. One time it was Maia and Luke, Maia looking slightly annoyed and Luke concerned. Another, there was a red haired woman next to Luke who was about his age. The other time, Nico could have sworn Rachel Elizabeth Dare was drawing in the air. He couldn't make sense of that at all. Why would Rachel be here?  
Nico's mind didn't give him time to think about it as he fell asleep once again.

The next time he woke up, it was Maia shaking him.

"I'm up, Hazel!" he groaned.

Maia frowned. "I'm not Hazel. Who's Hazel?" Nico opened his eyes and saw that is was indeed not Hazel. He blinked a few times.

"Hazel's my sister. Where – where am I? Maia?"

"Yeah, it's me." Maia said. "Do you remember what happened?"

"I –" Nico shook his head. "No." Maia sighed.

"There was a fight. You used some weird powers and then you fell unconscious. Seriously Nico, next time you decide to summon the freaking dead, tell us."

Nico internally groaned. Of course he had revealed his powers to everyone. Why not? Couldn't the fates just leave him alone? "Yeah…" he said. "Sorry about that. No one got hurt did they?"

"No." a blonde boy confirmed. "Only you and the demons."

"I tried to put a rune on you." Stated the Rachel lookalike. "But you had a violent reaction. Almost like a demon."

Nico froze. "You're saying I'm a demon?" she quickly shook her head.

"No of course not! You just reacted to the healing rune as someone with demonic blood would."

"I think you're forgetting he's a werewolf." Maia said sarcastically. "You know, they originated from demons like all downworlders."

"I'm not trying to offend anyone!" Rachel imposter cried. "I'm just saying what happened. "This is a rune I designed especially for downworlders so you can have the same healing capabilities as shadowhunters, and it didn't work on him."

A pale boy – Simon if Nico remembered correctly – peered over at him. "You said you were a warlock too."

"He what?" Maia asked incredulously. "A warlock?" all faces turned towards him.

"Yeah…" he said. "I'm a warlock and I guess a werewolf too. I got bitten a couple of months ago."

"But – what kind of magic do you have? Where's your mark?" Alec lightwood enquired suspiciously. "Magnus has his cat eyes and Catarina has her blue skin and Ragnor has his horns. Where's your warlock mark?"

Nico mentally searched his body for something unusual. There wasn't really anything unless you counted his weirdly pale skin which he didn't.

"Maybe he's like Tessa Gray?" Rachel suggested.

"Who's that?" Jace asked in confusion.

"She's a warlock the consul introduced me to after the war." She replied. "Tessa is the child of a demon and a shadowhunter so she has no mark but she can't bear shadowhunter runes. She also married your ancestor Will actually."

"Okay then… what relevance does that have?"

"None really." Alec said.

Nico sat up wearily and watched them all discussing him. They were shouting now, each trying to explain his 'magic'. He got the feeling shadowhunters didn't like not knowing what was going on. Then Alec turned to him.

"So what magic do you have? Is it fire like Magnus?"

"Um…" Nico glanced pleadingly at Simon. Alec noticed and whipped round to him.

"Do you know vampire?"

"I – yeah, but its Nico's secret to tell."

"So why doesn't he tell it?"

"Fine I will!" Nico shouted as loud as he could (which wasn't very loud in his present state.) "I have death magic. I can raise the dead and control the shadows. Think of something dark and evil, I can probably do it. Happy now?"

"So you're saying you're evil." Isabelle asked.

"What? No! Ugggh gods. Why did I even try? You know what? Could I just be left alone, please?"

"Uh sure…" she said, motioning for the others to follow her.

Miles away, night fell over a corner of long island, cloaking the landscape in a blanket of impenetrable darkness. The entirety of camp half blood was pitch black with the exception of a single window which threw a dim light across the grass outside. The window belonged to the big house where a few campers were huddled round a table still discussing the disappearance of the son of Hades. He had been gone now for about a week and even Chiron was getting worried. Nico di Angelo had never been one for socialising, and he had run away before, but that was then. Surely he wouldn't now, after all the campers had been through together? Chiron sighed. The only campers left now were Percy (and by default Annabeth), Will and Jason. Will looked like he had been crying and for all Chiron knew, he had been. He sighed again.

"Why don't you go to bed?" he asked Percy quietly. "This discussion isn't really going anywhere and you need sleep."

"No!" Percy cried. "We have to find Nico!"

Annabeth laid her hand gently on Percy's shoulder. "Chiron's right seaweed brain. You haven't slept in two days and you're starting to look like a zombie. You two Will." she gestured to the son of Apollo who had huge bags under his blue eyes. "This won't help find Nico."

"But we have to!" Percy pleaded. "We have to find him!"

"We're doing everything we can." Annabeth replied. "We have teams scouring New York, Hades has been notified and Reyna and Frank have the romans looking too. We just have to wait."

Percy nodded hopelessly. He trudged out of the door in the direction of the Poseidon cabin. Will sighed and followed him. Annabeth's eyes met Chiron's and she shrugged.

"What about the body we found?" she asked.

"The Apollo cabin looked over it." Chiron said. "They found evidence of scratch marks and claws. Kayla couldn't understand."

"You don't think…"

"It is possible child, it is possible. We will just have to wait and see."

 **Suspense! Now I'll have to update quickly because if you're anything like me then you'll hate waiting for the next bit. Hope you liked it.**


	6. Chapter 6

**Whooo! An update! It's about time. In this chapter, we get a tragic backstory and a special guest. Hope you like it!**

 **disclaimer: I own nothing except the plot. Cassandra Clare and Rick Riordan can take the rest of the credit.  
**  
"So Nico." Maia leaned forward on her elbows, getting uncomfortably close to Nico's face. "Now that you're a fancy warlock, can you magic all my troubles away?"

The latter mentioned 'warlock' groaned. "That's not how it works, Maia. I've told you – about a million times – I can't do the kind of magic you see in books. I can raise the dead and I can control shadows. That's it."

Maia grinned. "You can also turn into a giant furry monster!" she added. "I'm just teasing."

"I know." He sighed. "And I hate it."

"That's what friends are for!"

Nico glared at her. "I know that too. I hate it as well."

"You hate everything!"

"Do not!"

"Yes you do."

"Well, maybe you would if everything you ever knew and grew to love kept disappearing!" he retorted. He hadn't meant to say it – he had been trying his best to keep his past as much of a secret as possible. After all, this was supposed to be a new start.

He'd blown that.

Maia's face stopped laughing and her eyes grew concerned. "What do you mean?" she asked.

He was silent.

"Nico?"

"I don't want to talk about it."

His eyes were ducked down, deliberately ignoring hers. "Nico, it's okay. Everyone has their tragic history. Take me for example.

"You?" he mumbled quietly.

"Yes me." She replied. "I was born in new jersey – in a pile of toxic mush."

"I've never been to new jersey."

She laughed dryly. "Trust me, you don't want to. The community I grew up in was pretty bad – racist, violent. My parents favoured my older brother over me and refused to believe that he kept trying to hurt me. Then he… disappeared. I never really trusted boys after that."

"Maia – I – "

"It's fine. Like I said, we all have our backstories. Soon after that I met Jordan and, well. That's when I found out about the shadow world. He was amazing for the first few months but then he got weird. He became… possessive and rough. It ended with us breaking up. That was the night he got turned. I – I he bit me and… I turned too and here I am today." She sighed. "Like I say, tragic. We're fine now though. He turned up a year or so ago as Simon's roommate and we got back together after I dated Simon for a while."

Nico's attention was fully on her now. "Wow. That's…" he didn't seem to know how to act. "I'm sorry."

"It's fine." Maia shrugged. "I'm fine now."

"You know," Nico mused. "You remind me of someone. A friend of mine – Reyna. She helped me through a hard time too, showed me that I wasn't the only one struggling. She taught me to carry on and make the best of things."

"She sounds cool." Maia said.

"She is."

"Good to know."

Nico froze.

He recognised that voice.

That was… "Reyna!"

He whipped round in shock to meet the unamused face of Reyna Avilla Ramirez Arellano. She did not look overjoyed to see him.

She looked furious.

"Glad to know I inspire you, di Angelo. Now," Her voice was laced with menace and Nico shivered. "Care to tell us why you ran away from camp and made everyone – including Will solace – extremely worried and now you show up in a café in new York? Care to explain that, death boy?"

Nico gulped.

"Excuse me?" Maia put in. "Who are you? And how do you know Nico?"

Reyna laughed – it was not a pretty sound. "I would have thought you would know me since Nico here was just telling you all about me. I'm Reyna. Who are you?"

"…Maia."

"Nice to meet you. Now di Angelo, an explanation?"

"Reyna, look." Nico started. He glanced around. "Let's talk somewhere else. There's munda… mortals around."

"Fine." She said. "But you better explain."

"I will. Maia, can we go back to the jade wolf?"

"Sure." She answered.

"Jade wolf?" Reyna asked with an eyebrow raised.

"You'll see." Maia grinned. Here was yet another person to confuse with glamours. Yay!

The three arrived outside the Chinese takeaway a half hour later.

"What is this?" Reyna asked incredulously. "You've brought me to a crappy Chinese restaurant."

Maia winked at Nico. This was noticed by the other girl. "What's the joke?" she asked.

"Think of it as the mist." Nico explained. "There's a glamour on this building."

"Glamour?"

"I said I'd explain later."

Reyna narrowed her eyes, but concentrated and soon, a tiny tiny hint of surprise graced her face.

"You weren't as funny as Nico." Maia muttered.

"I'm sorry?" Reyna asked, confused and slightly offended.

"Nico's face was much funnier the first time he saw through the glamour." She clarified.

"Okay…"

Nico stepped in front of the two girls, sensing an awkward moment that he wanted to avoid. "Reyna, welcome to the jade wolf. Headquarters to Manhattan's wolf pack."

His words had the expected effect.

"Wolf?" Reyna questioned. It wasn't a curious type of question. It was more like she was even angrier with Nico than she already was and she wasn't sure how to voice it. Like she was absolutely fuming with rage and incredulous at the same time.

Nico gulped once again.

"Yes. Wolf." He steadied his mind. "Reyna, I'm – I'm a werewolf."

Reyna stared at him.

One second passed.

Two seconds.

Five seconds.

Ten seconds.

Thirty seconds.

"What?"

* * *

"And that's what happened." Nico finished with a slight uncharacteristic flourish.

He really had changed in these last few weeks, Reyna thought. Aside from apparently being a werewolf, (which wasn't completely ridiculous – the two of them did have a history with the creatures and the information she got about scratches did come from Dakota who was less than reliable) he seemed more at ease now. More ready to open up.

Reyna got the feeling she had missed a lot.

She learned of the shadow world which again, wasn't unbelievable given that she herself was a half god commander of the roman army who regularly fought mythical monsters. Apparently every person in this 'headquarters' was actually a werewolf including Maia who seemed… over enthusiastic. That was one way to describe her.

"Nico." She said. "That's…" Reyna had no idea how to respond.

"I get it." He said. "You're mad. I was a coward and I ran away and now everyone's looking for me."

"I'm not mad!" she assured him. "I'm just a little overwhelmed. That's all."

"Oh well… that's good."

An awkward silence ensued.

"Hey Nico?" Maia said, breaking it. "Luke wants to talk to you."

Both the demigods sent her a grateful look as she dragged Nico off to where Luke was waiting.

Reyna sighed. How should she deal with this? All of her life, she had been forced to make decisions that couldn't please everyone. She was good under pressure and she was good at taking multiple factors into consideration when making plans.

She always knew what to do

She just couldn't deal when she didn't.

A flickering in the air caught her eye. "Reyna, what's your status? Anything to report?" the gruff voice of Frank Zhang asked her.

Should she tell him?

Should she tell him that she had found Nico?

"No. I'm still searching. Have any of the teams found anything?"

Frank shook his head, looking worried. Reyna's throat felt tight.

"I'll update tomorrow." She said. "Regroup in two days."

"Okay." He confirmed. "See you then."

"See you." She whispered as the shimmering image faded away.

What was she going to do?

 **We** **all know it's bad when Reyna doesnt know what to do. I think that last sentence applies to my plans for this story. I have absolutely no idea where I'm going with it. I mean, it was only meant to be one chapter! Never mind. I'll think of something when I update in another month (sorry about that).**


	7. Chapter 7

****Ok. So first of all, I want to say I'm really sorry for not updating for ages. I've been swamped with school stuff and I got into a couple of new fandoms which took over my life... yeah. Sorry. Anyway, on a more positive note, I finally got round to writing this and we get a little insight into Reyna's mind. I really love Reyna. Hope you enjoy!****

 ** **Disclaimer: I own neither Percy Jackson or The Mortal Instruments. I guess shadowhunters (the tv show) should be included in this too since I'm using aspects of it, so I dont own that either.****

Reyna did regroup eventually and did not tell Frank of her findings. Instead, she told him she would carry on searching in the New York area and get back to him when she did find something. The lie almost convinced her.

She met back up with Nico and his werewolf friend Maia who immediately launched into various stories about the son of Hades, the said demigod looking very uncomfortable as she did so. Reyna found their presence strangely comforting – the casual banter and talk provided and easy distraction from the thoughts plaguing her brain and it was nice to see Nico so confident in himself and so at ease with another person. Reyna inwardly cursed the stupid maternal instinct she seemed to have developed when it came to Nico. She had a reputation, for the god's sakes!

She soon moved into Nico's flat when he mentioned that it had a handy second bedroom which saved the bother of having to rent her own. They had a comfortable arrangement where they avoided each other in the early morning because, as they discovered early on, neither were fit to be in human company before both nine o clock and coffee, and spent the day walking around new York or spending time with Maia and the other wolves. Most evenings, she and Nico went out to a nearby park and, covered in very convenient Mist, trained. Well, she trained; most of the time Nico was too lazy. Then again, he did spend some of his day doing whatever the wolves did to keep them battle worthy and fit which wasn't a complete waste of time, Reyna thought as she watched them practice slipping into their alternate forms.

It was strange, watching them train and seeing a rather majestic ebony wolf where Nico had been just a few seconds ago. Reyna couldn't quite get her head around it which made no sense, given that she worked with Frank Zhang.

Her life was overly confusing and she'd given up on sense a long time ago.

The days passed quickly in this strange new lifestyle and soon she realised, with a tiny hint of guilt, that she'd been away from camp for almost three weeks. That was when she met the rest of Nico's new friends.

She'd been told about the shadowhunters when Maia had given her an education on the down world and the things associated with it. Maia had been more than a little biased, talking with slight vehement, but Reyna got the impression that these shadowhunters were a little like demigods. Except, apparently, they hunted demons.

She was slightly apprehensive when Nico had announced that he was going to introduce her to two mysterious people called 'Clary' and 'Jace' who turned out to be not so mysterious as ridiculous as they bantered back and forth at the café Nico had chosen for them to meet. They so closely resembled Percy Jackson and Annabeth Chase that she almost laughed, although she could see some of Octavian in the smug swagger and self-obsession of Jace which made her cautious around him.

The rest of the shadowhunters she met at a later date and was surprised to see that only two out of the remaining four were actually shadowhunters at all. The species of one of them was made quite clear when he ordered a glass of blood at the local downworlders café, but the other Reyna couldn't work out for the life of her. She eventually deduced that he was some type of fearsome glitter monster which sent Nico into peals of unexpected laughter when she told him. He then, through heavy wheezes, informed her that he was in fact a warlock. A very glamourous one apparently. Nico liked his fashion sense. Reyna didn't.

She hardly noticed the other two shadowhunters, mostly because they looked almost entirely the same apart from the obvious gender difference. They were both dark haired and blue eyed and rather attractive. Average height, nothing to write home about.

Reyna's opinion changed drastically when she saw the girl fight. She unravelled a whip from seemingly nowhere and began to dance, weaving as the leather strip cut through the air – and the demons. Reyna couldn't help but watch in awe and after that, she spent many a day discussing fighting techniques with Isabelle Lightwood. Her brother Alec proved to be just as skilful, if a little more broody. He reminded Reyna a lot of Nico in that respect.

* * *

Nico was enjoying life, possibly for the first time since Bianca's death. He had friends and a whole pack of people who cared about him and he finally felt some sort of belonging with the wolves. Perhaps it was because most of them were misfits too, or maybe it was just the strangeness of their situation and the openness with which they approached it. After all, you can't turn into a different animal with someone all the time and end up not knowing them at all.

He actually found himself enjoying switching between his human and wolf form and it was interesting to try out his demigod powers as a wolf. After some testing, he worked out that while he could shadowtravel, a muzzle and paws was not any good for holding a sword. Of course, when he found that out, Maia pointed out that it was sort of obvious in the first place and she was soon subject to his best death glare.

He was good at death glares.

All was going well. He trained both with the wolves and Reyna, improving his fighting tenfold and he made reluctant friends with Maia's friends although some were slightly suspicious of him (Simon and Magnus) and some were just overly arrogant about everything (Jace).

About two weeks after Reyna found them, Magnus confronted him again.

Slightly ironically, it was in the same café as the previous confrontation and Magnus sat before him, very hard to take seriously with his cocktail and glittering…well… everything.

"So" he said in what was supposedly meant to be a menacing voice. "What are you?"

"I thought," Nico answered, "that I had already told you – I'm a warlock."

Magnus glared at him, looking rather attractive in his glittery eyeliner, but not at all threatening. "But you're not."

Nico raised an eyebrow. "I'm not?"

"No. You're not."

"And you know this because?"

"You have no mark, no magical signature, not anything that defines a warlock. Even people like Tessa Gray had some sort of magical signature I could latch on to."

Nico frowned in what he hoped looked like confusion. "But you said you could sense magic. And," he continued, becoming more confident, "you saw me use it."

"That was not magic." Magnus said. "Whatever it was, it wasn't magic. I know magic."

"You seemed pretty convinced then."

"That was before I saw you fight. No warlock uses a sword and armour. No warlock fights like you do. You don't just rely on magic as a warlock would. You've clearly been trained in combat."

"I'm a wolf." Nico pointed out. "We get trained." This was beginning to get annoying.

Magnus glared again. "Not to that level. It was more controlled than a wolf. Wolves fight feral, relying on instincts."

"You seem to be pretty into fighting techniques considering you're not a wolf and you know nothing about me."

"That's what I'm trying to find out." Magnus exclaimed. "Besides, I'm eight hundred years old and I get bored easily. I've studied most fighting ways. In fact, one of the only ones I've not studied is those of the ancient Peruvians."

"Why?"

"Long story. No time. Well, lots of time, but I'm interrogating you so shut up."

"It seems that you haven't matured in eight hundred years."

"It seems that you've matured too much in ninety."

At the shock dawning on Nico's face at that comment, Magnus grinned. "Did you forget that you told me that?"

Nico nodded blindly. Then he shot up. "Surely," he said, "That is proof that I am a warlock? They're immortal right, and they don't age after a certain point."

"But," Magnus said, as if explaining something to an impatient child, "you have way too much control for someone of ninety – most warlocks would need at least two centuries - and besides, I already know what you are."

"You do?"

"Yes. I told you I'd studied fighting didn't I? I would recognise a demigod anywhere. I just can't figure out if you're Roman or Greek. Definitely not Norse and the Egyptians don't really have them… unless you have Anubis… no. Don't think so."

Nico let out a little choked groan. "Norse, Egyptian?"

"Ah shoot." Magnus muttered. "I forgot you didn't know about each other. Try to forget what I just said?"

"Norse gods are real too?"

"Oh for god's sake, well, I guess given our conversations, for the __god's__ sakes, can we just get back to what we're talking about – you. Are you Roman or Greek?"

"Why should I tell you?"

"Definitely Hades or Pluto. Gods, you're just like your father. Sullen and mistrusting. Nice guy. He's got a good dog."

"You've met my father?"

"Well yeah. I'm immortal, he's immortal; we have big immortal parties down in the underworld. He's got a great palace."

"I know." Nico said. "I live there."

"So which is it?"

"Excuse me?"

"Roman or Greek. Which one are you?" he asked.

"Greek if you really want to know."

"Really?" Magnus looked surprised. "But your friend – the other demigod. She's almost the perfect Roman."

"You know about Reyna? Of course you do. She is Roman – daughter of Bellona – but she's one of my best friends and I spent some time in the Roman camp anyway."

"I thought…"

"We didn't know about each other? My father told me, and then a big flaming fireball fired down on New Rome from a flying ship by a Greek told everyone else. And then Gaia rose up and tried to destroy the earth and we had to work together to stop her and be united in friendship and all that rubbish. It sent my two best friends into Tartarus."

"Tartarus?" Magnus breathed.

"Big gloomy hellish place. The physical embodiment of hell and the primordial god. Ring any bells?" Nico snapped. It was clear to see he was getting worked up now.

"I know what it is." Magnus said. "I just thought nobody had gone down there."

"Well they have." Nico muttered. "And I did too."

"What?"

"Nothing." he growled.

Magnus noted, with some alarm, that the shadows were flying about Nico's head at a dizzying speed, bones clattering against the floor.

"Calm down Nico," he warned, not wanting to see or feel the wrath of a son of Hades.

Said demigod didn't speak, only letting out an indignant shout which confirmed Magnus' fears – he was not at all calm, and not at all in control of his own actions. This was going to be dangerous.

Magnus immediately constructed shields around the area they were sitting in, and braced himself.

The wave hit him only a second later and he was thrown back by the power of it. He felt Nico's anguish, raw and powerful. He felt the wolf in him come bounding out, tired of lying in wait. He felt the terror of Tartarus in all its entirety and the fear Nico had had of himself his whole life.

He felt pain.

When the darkness receded, Magnus took a minute or so to gather himself before remembering the demigod and looking around frantically. Nico lay on the floor and after a panicked mental scan, Magnus let out a sigh of relief. He was unconscious, but alive. He carefully picked Nico up, laying him on the table and called Maia who he knew was Nico's friend. He figured she would be able to take better care of him. Magnus wove a protection spell around Nico's body, ensuring no further harm would come to him.

Then he heard a tiny gasp from outside his shield. A pair of brown eyes peered round the corner.

"Is he okay? What the hell just happened?"

Magnus groaned. "How much did you see, Lewis? How much did you hear?"

Simon Lewis looked to the ground sheepishly. "All of it."


End file.
